Patchwork Command line support for altering the log file location

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Submitter Matthew Fernandez
Date June 8, 2011, 2:32 a.m.
Message ID <BANLkTimkBR7ZNOGaUO1gDmq2haBO41ciZ0F+5tdXoSdUgTxB=g@mail.gmail.com>
Download mbox | patch
Permalink /patch/99355/
State New
Headers show

Comments

Matthew Fernandez - June 8, 2011, 2:32 a.m.
Add command line support for logging to a location other than /tmp/qemu.log.

With logging enabled (command line option -d), the log is written to
the hard-coded path /tmp/qemu.log. This patch adds support for writing
the log to a different location by passing the -D option.

Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
----

Thanks Kevin and Blue Swirl for the feedback. Amended patch is below.
On 7 June 2011 18:49, Kevin Wolf <kwolf@redhat.com> wrote:
> Am 05.06.2011 02:46, schrieb Matthew Fernandez:
>> So, to clarify, all text above the '----' is included as the commit
>> message and the sign off line should be in this section. All text
>> below the '----' before the first diff is treated as comments that are
>> not to be committed. Is this correct? If so I'll send through an
>> ammended patch with these changes.
>
> Yes, this is correct.
>
> Kevin
>
>>
>> On 4 June 2011 20:18, Blue Swirl <blauwirbel@gmail.com> wrote:
>>> On Tue, May 31, 2011 at 9:20 AM, Matthew Fernandez
>>> <matthew.fernandez@gmail.com> wrote:
>>>> Hi,
>>>>
>>>> The included patch adds command line support for logging to a location
>>>> other than /tmp/qemu.log. The diff is relative to commit
>>>> 2eb9f241824d000fcd90bd7f4b49e40b88e62975. Please let me know if
>>>> anything needs to be cleaned up or changed. Anthony, I'm not sure who
>>>> should be responsible for reviewing/accepting this, but I've CCed you
>>>> as it touches vl.c.
>>>
>>> The patch looks OK, however the above text (which git-am would use as
>>> the commit message) needs to be changed. How about something like
>>> this:
>>> Add command line support for logging to a location other than /tmp/qemu.log.
>>>
>>> If you want to add comments which should not go to the commit message,
>>> please put them below the line with '----'.
>>>
>>>> Thanks,
>>>> Matthew
>>>>
>>>> ----
>>>> Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
>>>
>>> Also this needs to be above the  '----' line.



     }
Blue Swirl - June 15, 2011, 4:54 p.m.
Thanks, applied.

On Wed, Jun 8, 2011 at 5:32 AM, Matthew Fernandez
<matthew.fernandez@gmail.com> wrote:
> Add command line support for logging to a location other than /tmp/qemu.log.
>
> With logging enabled (command line option -d), the log is written to
> the hard-coded path /tmp/qemu.log. This patch adds support for writing
> the log to a different location by passing the -D option.
>
> Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
> ----
>
> Thanks Kevin and Blue Swirl for the feedback. Amended patch is below.
> On 7 June 2011 18:49, Kevin Wolf <kwolf@redhat.com> wrote:
>> Am 05.06.2011 02:46, schrieb Matthew Fernandez:
>>> So, to clarify, all text above the '----' is included as the commit
>>> message and the sign off line should be in this section. All text
>>> below the '----' before the first diff is treated as comments that are
>>> not to be committed. Is this correct? If so I'll send through an
>>> ammended patch with these changes.
>>
>> Yes, this is correct.
>>
>> Kevin
>>
>>>
>>> On 4 June 2011 20:18, Blue Swirl <blauwirbel@gmail.com> wrote:
>>>> On Tue, May 31, 2011 at 9:20 AM, Matthew Fernandez
>>>> <matthew.fernandez@gmail.com> wrote:
>>>>> Hi,
>>>>>
>>>>> The included patch adds command line support for logging to a location
>>>>> other than /tmp/qemu.log. The diff is relative to commit
>>>>> 2eb9f241824d000fcd90bd7f4b49e40b88e62975. Please let me know if
>>>>> anything needs to be cleaned up or changed. Anthony, I'm not sure who
>>>>> should be responsible for reviewing/accepting this, but I've CCed you
>>>>> as it touches vl.c.
>>>>
>>>> The patch looks OK, however the above text (which git-am would use as
>>>> the commit message) needs to be changed. How about something like
>>>> this:
>>>> Add command line support for logging to a location other than /tmp/qemu.log.
>>>>
>>>> If you want to add comments which should not go to the commit message,
>>>> please put them below the line with '----'.
>>>>
>>>>> Thanks,
>>>>> Matthew
>>>>>
>>>>> ----
>>>>> Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
>>>>
>>>> Also this needs to be above the  '----' line.
>
>
>
> diff --git a/bsd-user/main.c b/bsd-user/main.c
> index 0c3fca1..0af8a7e 100644
> --- a/bsd-user/main.c
> +++ b/bsd-user/main.c
> @@ -690,7 +690,8 @@ static void usage(void)
>            "-bsd type         select emulated BSD type
> FreeBSD/NetBSD/OpenBSD (default)\n"
>            "\n"
>            "Debug options:\n"
> -           "-d options   activate log (logfile=%s)\n"
> +           "-d options   activate log (default logfile=%s)\n"
> +           "-D logfile   override default logfile location\n"
>            "-p pagesize  set the host page size to 'pagesize'\n"
>            "-singlestep  always run in singlestep mode\n"
>            "-strace      log system calls\n"
> @@ -731,6 +732,8 @@ int main(int argc, char **argv)
>  {
>     const char *filename;
>     const char *cpu_model;
> +    const char *log_file = DEBUG_LOGFILE;
> +    const char *log_mask = NULL;
>     struct target_pt_regs regs1, *regs = &regs1;
>     struct image_info info1, *info = &info1;
>     TaskState ts1, *ts = &ts1;
> @@ -745,9 +748,6 @@ int main(int argc, char **argv)
>     if (argc <= 1)
>         usage();
>
> -    /* init debug */
> -    cpu_set_log_filename(DEBUG_LOGFILE);
> -
>     if ((envlist = envlist_create()) == NULL) {
>         (void) fprintf(stderr, "Unable to allocate envlist\n");
>         exit(1);
> @@ -775,22 +775,15 @@ int main(int argc, char **argv)
>         if (!strcmp(r, "-")) {
>             break;
>         } else if (!strcmp(r, "d")) {
> -            int mask;
> -            const CPULogItem *item;
> -
> -            if (optind >= argc)
> +            if (optind >= argc) {
>                 break;
> -
> -            r = argv[optind++];
> -            mask = cpu_str_to_log_mask(r);
> -            if (!mask) {
> -                printf("Log items (comma separated):\n");
> -                for(item = cpu_log_items; item->mask != 0; item++) {
> -                    printf("%-10s %s\n", item->name, item->help);
> -                }
> -                exit(1);
>             }
> -            cpu_set_log(mask);
> +            log_mask = argv[optind++];
> +        } else if (!strcmp(r, "D")) {
> +            if (optind >= argc) {
> +                break;
> +            }
> +            log_file = argv[optind++];
>         } else if (!strcmp(r, "E")) {
>             r = argv[optind++];
>             if (envlist_setenv(envlist, r) != 0)
> @@ -867,6 +860,23 @@ int main(int argc, char **argv)
>         usage();
>     filename = argv[optind];
>
> +    /* init debug */
> +    cpu_set_log_filename(log_file);
> +    if (log_mask) {
> +        int mask;
> +        const CPULogItem *item;
> +
> +        mask = cpu_str_to_log_mask(r);
> +        if (!mask) {
> +            printf("Log items (comma separated):\n");
> +            for (item = cpu_log_items; item->mask != 0; item++) {
> +                printf("%-10s %s\n", item->name, item->help);
> +            }
> +            exit(1);
> +        }
> +        cpu_set_log(mask);
> +    }
> +
>     /* Zero out regs */
>     memset(regs, 0, sizeof(struct target_pt_regs));
>
> diff --git a/cpus.c b/cpus.c
> index 1fc34b7..17e96b5 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -1142,6 +1142,11 @@ void set_cpu_log(const char *optarg)
>     cpu_set_log(mask);
>  }
>
> +void set_cpu_log_filename(const char *optarg)
> +{
> +    cpu_set_log_filename(optarg);
> +}
> +
>  /* Return the virtual CPU time, based on the instruction counter.  */
>  int64_t cpu_get_icount(void)
>  {
> diff --git a/cpus.h b/cpus.h
> index 6fdeb0d..f42b54e 100644
> --- a/cpus.h
> +++ b/cpus.h
> @@ -19,6 +19,7 @@ void vm_state_notify(int running, int reason);
>  bool cpu_exec_all(void);
>  void set_numa_modes(void);
>  void set_cpu_log(const char *optarg);
> +void set_cpu_log_filename(const char *optarg);
>  void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg);
>
>  #endif
> diff --git a/darwin-user/main.c b/darwin-user/main.c
> index 175e12f..a6dc859 100644
> --- a/darwin-user/main.c
> +++ b/darwin-user/main.c
> @@ -738,6 +738,8 @@ TaskState *first_task_state;
>  int main(int argc, char **argv)
>  {
>     const char *filename;
> +    const char *log_file = DEBUG_LOGFILE;
> +    const char *log_mask = NULL;
>     struct target_pt_regs regs1, *regs = &regs1;
>     TaskState ts1, *ts = &ts1;
>     CPUState *env;
> @@ -749,9 +751,6 @@ int main(int argc, char **argv)
>     if (argc <= 1)
>         usage();
>
> -    /* init debug */
> -    cpu_set_log_filename(DEBUG_LOGFILE);
> -
>     optind = 1;
>     for(;;) {
>         if (optind >= argc)
> @@ -764,22 +763,15 @@ int main(int argc, char **argv)
>         if (!strcmp(r, "-")) {
>             break;
>         } else if (!strcmp(r, "d")) {
> -            int mask;
> -            CPULogItem *item;
> -
> -        if (optind >= argc)
> -        break;
> -
> -        r = argv[optind++];
> -            mask = cpu_str_to_log_mask(r);
> -            if (!mask) {
> -                printf("Log items (comma separated):\n");
> -                for(item = cpu_log_items; item->mask != 0; item++) {
> -                    printf("%-10s %s\n", item->name, item->help);
> -                }
> -                exit(1);
> +            if (optind >= argc) {
> +                break;
>             }
> -            cpu_set_log(mask);
> +            log_mask = argv[optind++];
> +        } else if (!strcmp(r, "D")) {
> +            if (optind >= argc) {
> +                break;
> +            }
> +            log_file = argv[optind++];
>         } else if (!strcmp(r, "s")) {
>             r = argv[optind++];
>             stack_size = strtol(r, (char **)&r, 0);
> @@ -821,6 +813,23 @@ int main(int argc, char **argv)
>         usage();
>     filename = argv[optind];
>
> +    /* init debug */
> +    cpu_set_log_filename(log_file);
> +    if (log_mask) {
> +        int mask;
> +        CPULogItem *item;
> +
> +        mask = cpu_str_to_log_mask(r);
> +        if (!mask) {
> +            printf("Log items (comma separated):\n");
> +            for (item = cpu_log_items; item->mask != 0; item++) {
> +                printf("%-10s %s\n", item->name, item->help);
> +            }
> +            exit(1);
> +        }
> +        cpu_set_log(mask);
> +    }
> +
>     /* Zero out regs */
>     memset(regs, 0, sizeof(struct target_pt_regs));
>
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 088def3..23c229c 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -2848,6 +2848,8 @@ int main(int argc, char **argv, char **envp)
>  {
>     const char *filename;
>     const char *cpu_model;
> +    const char *log_file = DEBUG_LOGFILE;
> +    const char *log_mask = NULL;
>     struct target_pt_regs regs1, *regs = &regs1;
>     struct image_info info1, *info = &info1;
>     struct linux_binprm bprm;
> @@ -2869,9 +2871,6 @@ int main(int argc, char **argv, char **envp)
>
>     qemu_cache_utils_init(envp);
>
> -    /* init debug */
> -    cpu_set_log_filename(DEBUG_LOGFILE);
> -
>     if ((envlist = envlist_create()) == NULL) {
>         (void) fprintf(stderr, "Unable to allocate envlist\n");
>         exit(1);
> @@ -2910,22 +2909,15 @@ int main(int argc, char **argv, char **envp)
>         if (!strcmp(r, "-")) {
>             break;
>         } else if (!strcmp(r, "d")) {
> -            int mask;
> -            const CPULogItem *item;
> -
> -           if (optind >= argc)
> +            if (optind >= argc) {
>                break;
> -
> -           r = argv[optind++];
> -            mask = cpu_str_to_log_mask(r);
> -            if (!mask) {
> -                printf("Log items (comma separated):\n");
> -                for(item = cpu_log_items; item->mask != 0; item++) {
> -                    printf("%-10s %s\n", item->name, item->help);
> -                }
> -                exit(1);
>             }
> -            cpu_set_log(mask);
> +            log_mask = argv[optind++];
> +        } else if (!strcmp(r, "D")) {
> +            if (optind >= argc) {
> +                break;
> +            }
> +            log_file = argv[optind++];
>         } else if (!strcmp(r, "E")) {
>             r = argv[optind++];
>             if (envlist_setenv(envlist, r) != 0)
> @@ -3038,6 +3030,23 @@ int main(int argc, char **argv, char **envp)
>     filename = argv[optind];
>     exec_path = argv[optind];
>
> +    /* init debug */
> +    cpu_set_log_filename(log_file);
> +    if (log_mask) {
> +        int mask;
> +        const CPULogItem *item;
> +
> +        mask = cpu_str_to_log_mask(r);
> +        if (!mask) {
> +            printf("Log items (comma separated):\n");
> +            for (item = cpu_log_items; item->mask != 0; item++) {
> +                printf("%-10s %s\n", item->name, item->help);
> +            }
> +            exit(1);
> +        }
> +        cpu_set_log(mask);
> +    }
> +
>     /* Zero out regs */
>     memset(regs, 0, sizeof(struct target_pt_regs));
>
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 82e085a..05513e8 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1991,6 +1991,15 @@ STEXI
>  Output log in /tmp/qemu.log
>  ETEXI
>
> +DEF("D", HAS_ARG, QEMU_OPTION_D, \
> +    "-D logfile      output log to logfile (instead of the default
> /tmp/qemu.log)\n",
> +    QEMU_ARCH_ALL)
> +STEXI
> +@item -D
> +@findex -D
> +Output log in logfile instead of /tmp/qemu.log
> +ETEXI
> +
>  DEF("hdachs", HAS_ARG, QEMU_OPTION_hdachs, \
>     "-hdachs c,h,s[,t]\n" \
>     "                force hard disk 0 physical geometry and the
> optional BIOS\n" \
> diff --git a/vl.c b/vl.c
> index b362871..e459f64 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2060,6 +2060,8 @@ int main(int argc, char **argv, char **envp)
>  #endif
>     int defconfig = 1;
>     const char *trace_file = NULL;
> +    const char *log_mask = NULL;
> +    const char *log_file = NULL;
>
>     atexit(qemu_run_exit_notifiers);
>     error_set_progname(argv[0]);
> @@ -2434,7 +2436,10 @@ int main(int argc, char **argv, char **envp)
>                 break;
>  #endif
>             case QEMU_OPTION_d:
> -                set_cpu_log(optarg);
> +                log_mask = optarg;
> +                break;
> +            case QEMU_OPTION_D:
> +                log_file = optarg;
>                 break;
>             case QEMU_OPTION_s:
>                 gdbstub_dev = "tcp::" DEFAULT_GDBSTUB_PORT;
> @@ -2900,6 +2905,18 @@ int main(int argc, char **argv, char **envp)
>     }
>     loc_set_none();
>
> +    /* Open the logfile at this point, if necessary. We can't open the logfile
> +     * when encountering either of the logging options (-d or -D) because the
> +     * other one may be encountered later on the command line, changing the
> +     * location or level of logging.
> +     */
> +    if (log_mask) {
> +        if (log_file) {
> +            set_cpu_log_filename(log_file);
> +        }
> +        set_cpu_log(log_mask);
> +    }
> +
>     if (!st_init(trace_file)) {
>         fprintf(stderr, "warning: unable to initialize simple trace
> backend\n");
>     }
>
Edgar Iglesias - June 28, 2011, 6:33 p.m.
On Wed, Jun 08, 2011 at 12:32:40PM +1000, Matthew Fernandez wrote:
> Add command line support for logging to a location other than /tmp/qemu.log.
> 
> With logging enabled (command line option -d), the log is written to
> the hard-coded path /tmp/qemu.log. This patch adds support for writing
> the log to a different location by passing the -D option.
> 
> Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>


Hi,

This patch broke -d for all *-user targets AFAICT.
r is passed to cpu_str_to_log_mask(r) instead of log_mask.

Cheers


>          } else if (!strcmp(r, "d")) {
> -            int mask;
> -            const CPULogItem *item;
> -
> -            if (optind >= argc)
> +            if (optind >= argc) {
>                  break;
> -
> -            r = argv[optind++];
> -            mask = cpu_str_to_log_mask(r);
> -            if (!mask) {
> -                printf("Log items (comma separated):\n");
> -                for(item = cpu_log_items; item->mask != 0; item++) {
> -                    printf("%-10s %s\n", item->name, item->help);
> -                }
> -                exit(1);
>              }
> -            cpu_set_log(mask);
> +            log_mask = argv[optind++];
> +        } else if (!strcmp(r, "D")) {
> +            if (optind >= argc) {
> +                break;
> +            }
> +            log_file = argv[optind++];
>          } else if (!strcmp(r, "E")) {
>              r = argv[optind++];
>              if (envlist_setenv(envlist, r) != 0)
> @@ -867,6 +860,23 @@ int main(int argc, char **argv)
>          usage();
>      filename = argv[optind];
> 
> +    /* init debug */
> +    cpu_set_log_filename(log_file);
> +    if (log_mask) {
> +        int mask;
> +        const CPULogItem *item;
> +
> +        mask = cpu_str_to_log_mask(r);

Patch

diff --git a/bsd-user/main.c b/bsd-user/main.c
index 0c3fca1..0af8a7e 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -690,7 +690,8 @@  static void usage(void)
            "-bsd type         select emulated BSD type
FreeBSD/NetBSD/OpenBSD (default)\n"
            "\n"
            "Debug options:\n"
-           "-d options   activate log (logfile=%s)\n"
+           "-d options   activate log (default logfile=%s)\n"
+           "-D logfile   override default logfile location\n"
            "-p pagesize  set the host page size to 'pagesize'\n"
            "-singlestep  always run in singlestep mode\n"
            "-strace      log system calls\n"
@@ -731,6 +732,8 @@  int main(int argc, char **argv)
 {
     const char *filename;
     const char *cpu_model;
+    const char *log_file = DEBUG_LOGFILE;
+    const char *log_mask = NULL;
     struct target_pt_regs regs1, *regs = &regs1;
     struct image_info info1, *info = &info1;
     TaskState ts1, *ts = &ts1;
@@ -745,9 +748,6 @@  int main(int argc, char **argv)
     if (argc <= 1)
         usage();

-    /* init debug */
-    cpu_set_log_filename(DEBUG_LOGFILE);
-
     if ((envlist = envlist_create()) == NULL) {
         (void) fprintf(stderr, "Unable to allocate envlist\n");
         exit(1);
@@ -775,22 +775,15 @@  int main(int argc, char **argv)
         if (!strcmp(r, "-")) {
             break;
         } else if (!strcmp(r, "d")) {
-            int mask;
-            const CPULogItem *item;
-
-            if (optind >= argc)
+            if (optind >= argc) {
                 break;
-
-            r = argv[optind++];
-            mask = cpu_str_to_log_mask(r);
-            if (!mask) {
-                printf("Log items (comma separated):\n");
-                for(item = cpu_log_items; item->mask != 0; item++) {
-                    printf("%-10s %s\n", item->name, item->help);
-                }
-                exit(1);
             }
-            cpu_set_log(mask);
+            log_mask = argv[optind++];
+        } else if (!strcmp(r, "D")) {
+            if (optind >= argc) {
+                break;
+            }
+            log_file = argv[optind++];
         } else if (!strcmp(r, "E")) {
             r = argv[optind++];
             if (envlist_setenv(envlist, r) != 0)
@@ -867,6 +860,23 @@  int main(int argc, char **argv)
         usage();
     filename = argv[optind];

+    /* init debug */
+    cpu_set_log_filename(log_file);
+    if (log_mask) {
+        int mask;
+        const CPULogItem *item;
+
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for (item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+
     /* Zero out regs */
     memset(regs, 0, sizeof(struct target_pt_regs));

diff --git a/cpus.c b/cpus.c
index 1fc34b7..17e96b5 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1142,6 +1142,11 @@  void set_cpu_log(const char *optarg)
     cpu_set_log(mask);
 }

+void set_cpu_log_filename(const char *optarg)
+{
+    cpu_set_log_filename(optarg);
+}
+
 /* Return the virtual CPU time, based on the instruction counter.  */
 int64_t cpu_get_icount(void)
 {
diff --git a/cpus.h b/cpus.h
index 6fdeb0d..f42b54e 100644
--- a/cpus.h
+++ b/cpus.h
@@ -19,6 +19,7 @@  void vm_state_notify(int running, int reason);
 bool cpu_exec_all(void);
 void set_numa_modes(void);
 void set_cpu_log(const char *optarg);
+void set_cpu_log_filename(const char *optarg);
 void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg);

 #endif
diff --git a/darwin-user/main.c b/darwin-user/main.c
index 175e12f..a6dc859 100644
--- a/darwin-user/main.c
+++ b/darwin-user/main.c
@@ -738,6 +738,8 @@  TaskState *first_task_state;
 int main(int argc, char **argv)
 {
     const char *filename;
+    const char *log_file = DEBUG_LOGFILE;
+    const char *log_mask = NULL;
     struct target_pt_regs regs1, *regs = &regs1;
     TaskState ts1, *ts = &ts1;
     CPUState *env;
@@ -749,9 +751,6 @@  int main(int argc, char **argv)
     if (argc <= 1)
         usage();

-    /* init debug */
-    cpu_set_log_filename(DEBUG_LOGFILE);
-
     optind = 1;
     for(;;) {
         if (optind >= argc)
@@ -764,22 +763,15 @@  int main(int argc, char **argv)
         if (!strcmp(r, "-")) {
             break;
         } else if (!strcmp(r, "d")) {
-            int mask;
-            CPULogItem *item;
-
-        if (optind >= argc)
-        break;
-
-        r = argv[optind++];
-            mask = cpu_str_to_log_mask(r);
-            if (!mask) {
-                printf("Log items (comma separated):\n");
-                for(item = cpu_log_items; item->mask != 0; item++) {
-                    printf("%-10s %s\n", item->name, item->help);
-                }
-                exit(1);
+            if (optind >= argc) {
+                break;
             }
-            cpu_set_log(mask);
+            log_mask = argv[optind++];
+        } else if (!strcmp(r, "D")) {
+            if (optind >= argc) {
+                break;
+            }
+            log_file = argv[optind++];
         } else if (!strcmp(r, "s")) {
             r = argv[optind++];
             stack_size = strtol(r, (char **)&r, 0);
@@ -821,6 +813,23 @@  int main(int argc, char **argv)
         usage();
     filename = argv[optind];

+    /* init debug */
+    cpu_set_log_filename(log_file);
+    if (log_mask) {
+        int mask;
+        CPULogItem *item;
+
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for (item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+
     /* Zero out regs */
     memset(regs, 0, sizeof(struct target_pt_regs));

diff --git a/linux-user/main.c b/linux-user/main.c
index 088def3..23c229c 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2848,6 +2848,8 @@  int main(int argc, char **argv, char **envp)
 {
     const char *filename;
     const char *cpu_model;
+    const char *log_file = DEBUG_LOGFILE;
+    const char *log_mask = NULL;
     struct target_pt_regs regs1, *regs = &regs1;
     struct image_info info1, *info = &info1;
     struct linux_binprm bprm;
@@ -2869,9 +2871,6 @@  int main(int argc, char **argv, char **envp)

     qemu_cache_utils_init(envp);

-    /* init debug */
-    cpu_set_log_filename(DEBUG_LOGFILE);
-
     if ((envlist = envlist_create()) == NULL) {
         (void) fprintf(stderr, "Unable to allocate envlist\n");
         exit(1);
@@ -2910,22 +2909,15 @@  int main(int argc, char **argv, char **envp)
         if (!strcmp(r, "-")) {
             break;
         } else if (!strcmp(r, "d")) {
-            int mask;
-            const CPULogItem *item;
-
-	    if (optind >= argc)
+            if (optind >= argc) {
 		break;
-
-	    r = argv[optind++];
-            mask = cpu_str_to_log_mask(r);
-            if (!mask) {
-                printf("Log items (comma separated):\n");
-                for(item = cpu_log_items; item->mask != 0; item++) {
-                    printf("%-10s %s\n", item->name, item->help);
-                }
-                exit(1);
             }
-            cpu_set_log(mask);
+            log_mask = argv[optind++];
+        } else if (!strcmp(r, "D")) {
+            if (optind >= argc) {
+                break;
+            }
+            log_file = argv[optind++];
         } else if (!strcmp(r, "E")) {
             r = argv[optind++];
             if (envlist_setenv(envlist, r) != 0)
@@ -3038,6 +3030,23 @@  int main(int argc, char **argv, char **envp)
     filename = argv[optind];
     exec_path = argv[optind];

+    /* init debug */
+    cpu_set_log_filename(log_file);
+    if (log_mask) {
+        int mask;
+        const CPULogItem *item;
+
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for (item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+
     /* Zero out regs */
     memset(regs, 0, sizeof(struct target_pt_regs));

diff --git a/qemu-options.hx b/qemu-options.hx
index 82e085a..05513e8 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1991,6 +1991,15 @@  STEXI
 Output log in /tmp/qemu.log
 ETEXI

+DEF("D", HAS_ARG, QEMU_OPTION_D, \
+    "-D logfile      output log to logfile (instead of the default
/tmp/qemu.log)\n",
+    QEMU_ARCH_ALL)
+STEXI
+@item -D
+@findex -D
+Output log in logfile instead of /tmp/qemu.log
+ETEXI
+
 DEF("hdachs", HAS_ARG, QEMU_OPTION_hdachs, \
     "-hdachs c,h,s[,t]\n" \
     "                force hard disk 0 physical geometry and the
optional BIOS\n" \
diff --git a/vl.c b/vl.c
index b362871..e459f64 100644
--- a/vl.c
+++ b/vl.c
@@ -2060,6 +2060,8 @@  int main(int argc, char **argv, char **envp)
 #endif
     int defconfig = 1;
     const char *trace_file = NULL;
+    const char *log_mask = NULL;
+    const char *log_file = NULL;

     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
@@ -2434,7 +2436,10 @@  int main(int argc, char **argv, char **envp)
                 break;
 #endif
             case QEMU_OPTION_d:
-                set_cpu_log(optarg);
+                log_mask = optarg;
+                break;
+            case QEMU_OPTION_D:
+                log_file = optarg;
                 break;
             case QEMU_OPTION_s:
                 gdbstub_dev = "tcp::" DEFAULT_GDBSTUB_PORT;
@@ -2900,6 +2905,18 @@  int main(int argc, char **argv, char **envp)
     }
     loc_set_none();

+    /* Open the logfile at this point, if necessary. We can't open the logfile
+     * when encountering either of the logging options (-d or -D) because the
+     * other one may be encountered later on the command line, changing the
+     * location or level of logging.
+     */
+    if (log_mask) {
+        if (log_file) {
+            set_cpu_log_filename(log_file);
+        }
+        set_cpu_log(log_mask);
+    }
+
     if (!st_init(trace_file)) {
         fprintf(stderr, "warning: unable to initialize simple trace
backend\n");